Miscarriage Causes: HLA Matching
A fundamental part of
HLA function is the presence of MHC molecules on all cells in the body. While there
must be great similarity between these
HLA genes with the donor and recipient during a transplant, this does not hold true
when considering an embryo. New literature has shown that there are immune
privileged sites in the body that generate tolerance for "grafted"
tissue through differences in Key HLA genes. These sites are the eye,
testicle and the uterus to name a few. There are reasons an embryo must
have significant differences than the mother in order for a pregnancy
to be successful and not result in miscarriage. Evolution has resulted
in significant variation in the shape and sizes of MHC molecules (It is
the MHC molecules that pick up virus and bacteria and present it to the
immune system for eradication). The variation of the MCH molecules prevents
a virus or bacteria from mutating and then evading the immune system in
every person they infect, preventing an entire population form getting
wiped out during an outbreak. Nature has a reason therefore to try and
reject an embryo in couples with similar HLA genes as this would eliminate
the ability to diversify.
Other HLA molecules on the Paternal sperm surface, however, play an important
role in beginning the process of immune tolerance. One theory is that
a difference between the HLA genes of the mother and the paternal sperm
and later the embryo tissue itself starts a mechanism for the generation
of tolerance in the mothers immune system .From here, there are a series
of events in the maternal immune system that turn off its attacking aspects
and actually develop cells to protect the embryo called T regulator cells.
Success After Multiple Miscarriages
Differences of HLA genes between the mother and the embryo depend on those
of the father, as it is a combination of each parents' genes which
determine those of the embryo. Dr. Braverman therefore checks the HLA
status of both parents to determine whether or not HLA matching is the
issue or other factors are responsible for the defective function of cells
and resultant recurrent miscarriages. Due to the way the immune system
works, attacks on the embryo due to HLA similarity may occur during early
pregnancy, later in pregnancies or even in future pregnancies. Our team
will take a comprehensive approach to increasing your ability to complete
pregnancies successfully.
Read our blog on HLA analysis.
Contact a reproductive specialist from Braverman IVF & Reproductive Immunology for an examination of
your HLA status and how this may be affecting your pregnancies.
View our informational video about this topic by clicking on the video
screen below or by
clicking here.